If you are using the popular 'Contact Form' plugin, try Settings > Contact Form (under Plugins heading) and the field you want is the first field, 'To Email'.
The variables in Globals are 100% custom but usually change the email address that is displayed sitewide such as in your footer or contact page. They can be, but are not necessarily, wired into your ...
I had the same problem and I found out - it is necessary to create a route.
You have two options for that:
Entry (single) with slug
Thats because redirectInput() redirect to an url. But without a route - you just can not access the template tree. Thats the whole point of a routing system.
I would love to see a custom route created (and ...